The present application is submitted to begin gathering systematic information on psychophysiologic aspects of male and female sexuality. An approach to the study of psychophysiologic processes related to sexuality is the consideration of physiologic varioations in genital organs is to obtain normative data on sex related physiologic changes during sleep in males and females free of sexual problems with the sim of applying these findings to the study of patients with sexual disorders. Studies are are proposed to obtain basic information on nocturnal penile tumescence and pituitary gonadal function during sleep in normal mem. These data will provide a basis for similar studies to be conducted on mem suffering from psychogenic impotency and impotency associated with diabetes. In addition to increasing our overall knowledge of the subject, the assessment of endocrine and penile tumescent changes in men with potency disorders may have diagnostic as well as prognostic significance. Studies concerning the psychophysiology of female sexuality will focus on th e measurement of vaginal blood flow as an indicator of sexual arousal and the gathering of normative data during wakefulness and in relation to stages of sleep. As with men, it is expected that these findings may provide a basis for the systematic investigation of physiological changes in women with sexual disorders.